The invention relates to a device for effectively removing suspended particles from an airflow, wherein the device comprises an intake opening, an air conveying duct, and a suction fan, and wherein the air conveying duct deflects sectionally the airflow with regard to its flow direction. The suspended particles can be created in particular by operation of stove devices and are removed by exhaust hoods of the aforementioned kind.
In the prior art, an exhaust hood is known that is comprised of an intake chamber and an exhaust chamber wherein a grease filter arranged in an air passage comprises a cleaning device with spray nozzles for spraying and a collecting channel for collecting and discharging cleaning liquids. The conventional exhaust hood, as disclosed in EP-A-0 703 414, is characterized by an angular arrangement of the exhaust chamber about a central intake chamber, wherein above a cover plate of the intake chamber the centrally arranged spraying device with spray nozzles is arranged through which the spray nozzles are supplied with liquid in order to remove solid and liquid particles from the airflow sucked in by the conventional exhaust hood.
The conventional exhaust hood, inter alia, has the disadvantage that a continuous consumption of washing agents and solvents is not required and the supply of washing agents and solvents must be controlled and monitored by metering devices, and that moreover the spraying device is comprised of a spraying arm with spraying nozzles that is arranged to be rotatable about a vertical axis, wherein the spraying arm in operation must be rotated at all times and these movements must also be monitored at all times.
Moreover, not only the supply of washing agents and solvents must be monitored, but moreover the washing agents and solvents that are laden with solid particles and liquid particles from the sucked-in airflow must be removed as wastewater. Therefore, the exhaust hood requires separate supply devices and removal devices for the washing agents and solvents and for the washing agents and solvents in the form of waste water.
The conventional exhaust hood requires an increased expenditure with regard to service as well as with regard to spatial size of the receptacle of the conventional exhaust hood; additionally, a comprehensive monitoring and servicing of the spraying and control devices of the conventional exhaust hood is required.
In the ventilation exhaust described in DE-OS 26 504 35, which is comprised of a primary chamber arranged above the stove and a secondary chamber that communicates with the primary chamber, the sucked-in airflow is guided through a filter underneath which filter nozzles are arranged. By means of these nozzles cleaning water is sprayed into the area below a grid provided as a filter for collecting and removing solid and liquid particles removed from the airflow.
The conventional ventilation exhaust also makes necessary special devices for supplying the cleaning water and the cleaning water laden with particles as wastewater as well as for removing. Also, the conventional ventilation exhaust requires devices for operating the grid used as a filter with spray nozzles. Moreover, it has been found that the moisture of the airflow that has been laden greatly with water molecules condensates also above the filter in the secondary chamber and in the ducts for removing the airflow from the secondary chamber to the exterior outside of the room where the stove devices are located.
The precipitation of moisture from the airflow enriched with water molecules leads often to fungal growth and bacterial growth. Fungal growth and bacterial growth contribute because of their spore generation to an increased health risk of the personnel present within the room where the conventional ventilation exhaust is located.
The kitchen exhaust hood disclosed in DE-OS 199 60 589 is characterized by an aerosol separator which is arranged opposite an intake opening wherein the housing has a cylinder having a wall in which the intake opening extends in the longitudinal direction of the cylinder underneath the guide surface wherein the aerosol separator opposite the intake opening forms a longitudinal section of the wall of the cylinder and the base surfaces of the cylinder each have outlet openings for the airflow above the exit side of the passage.
The configuration of the conventional kitchen exhaust hood is very complex in order to remove suspended particles, vapor and grease droplets, dust and soot particles from the airflow.
Finally, an exhaust hood is disclosed in DE 299 18 312 that comprises a housing with back plate, side plates, and a top plate wherein the top plate has at least one outlet opening and at least one motor attached thereto. This exhaust hood comprises a passage that communicates with the outlet opening wherein the passage has connected thereto an outlet chamber. Above the intake opening, a slanted bottom plate is arranged above which a separating device is arranged. The separating device communicates with at least one nozzle that is loaded with water for generating a water curtain. The taken-in airflow flows through the water curtain for the purpose of oil removal. The removed oil is contained in a collecting device.
It has been found here also that the airflow that is highly enriched with water molecules has the tendency of condensate formation in the area of the outlet opening and in the area of the exhaust lines connected to the outlet openings. Moreover, a further disadvantage is created, in addition to the requirement for supply, removal and control of the cleaning water, in that fungal and bacterial growth occur; this is to be avoided at all costs particularly in the area of foodstuff preparation and processing.
All of the aforementioned solutions have in common the disadvantage that, despite a high constructive expenditure, they can remove only comparatively minimal proportions of suspended particles from the taken-in air. In all solutions there remain residual amounts of suspended particles in the exhaust air that will deposit in the fan and air conveying ducts and will cause stubborn soiling that can hardly be removed anymore.